The fuel pump is typically mounted on the low side of an engine cylinder head such that oil pooling on the low side of the cylinder head is available to accumulate in the fuel pump tappet/roller follower mounting hole, thereby passively providing a source of lubrication to the fuel pump tappet/roller follower mounting hole and ensuring that oil is provided to the tappet/roller follower and to the sliding interface between cylinder head surface and the fuel pump tappet/roller follower. When engine packaging constraints exist which prohibit locating the fuel pump on the low side of the engine or require mounting the fuel pump in an engine location where oil drains away from or otherwise is not adequately provided to the tappet/roller follower sliding interface, alternative methods must be used to ensure a supply of oil lubricate the interface. For example, pressurized oil can be provided to the interface, which would require routing of oil to the fuel pump tappet/roller follower mounting hole, increasing demand from the oil pump and increasing the cost of the cylinder head. Providing pressurized oil may also result in excess oil pooling around the tappet/roller follower and creating the potential for hydraulic locking.